About a year ago I put an 11 speed XT M8000 shifter , derailleur and a 50t cassette on ,it’s been pretty good all this time, until about 2 weeks ago it became very erratic , so I went through all the paces I know that usually sort things , but not this time , it’s been an absolute pig to get it shifting properly up and dawn , it’s nearly there now just a sort of delay when going on to the 11 tooth sprocket , don’t use that a lot so it’s not a big issue but it’s been frustrating the crap out of me , I’ll do one more adjustment and tweak the limiter outboard a bit hopefully that will cure it ,

Mech hanger alignment?

ScotRoutes wrote: ↑Tue Sep 01, 2020 7:38 am Mech hanger alignment?

That would be one of my guesses too. Any 11 or indeed 12 speed system tends to be a little more sensitive to this.

Bent mech cage?

Also worn guide jockey, teeth or bush?

Tired spring in the mech and slightly too short chain? Unusual if it's been working well and only a year of abuse. But depends how much use a year is for you.

Kinked or damaged cable preventing the derailleur spring pushing the chain down? If you give the mech a little pull, does it then shift?

Would it be something as simple as you forgot to move the clutch lever to on after replacing the back wheel?
I do it all the time. I don't pretend to understand why because it is set up with clutch off but that lever just moves between a grindy horrible gear change and smooth silent (almost) gear change.

I've been suprised before by how much better everything works after I put new inners + outers on, even when the cables don't look too bad. Not dropping onto the smallest sprocket or shifting consistently or accurately can be a sign of dirty or draggy cables. Also, how much better Shimano cables function compared to some of the cheaper alternatives.

Agree with James - cable is the first thing I'd think of if it's struggling to hit the small cog. Take it out and give it a wipe and spray down the outer with a load of PTFE. Then throw outer and inner in the bin and put a new one on.

Yep new cables for sure. Ive had this and spent ages faffing. Then sorted it in minutes with new inners and outers

Thanks for replies fellas, it is a brand new Shimano cable , all good and outlers good ,
It is more than likely tension, Im hoping to get into a local bike hub in a bit to put the new head set bearings on, I’ll get the lad there to give it a quick once over